Laminated Film Interlayer Warping Suppression
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Solution Overview
Problem
Transparent heat-resistant laminated films used in flexible electronic devices face challenges with surface smoothness and handling properties, as they tend to warp due to differences in physical properties between layers, and existing methods to improve slipperiness, such as adding lubricants, compromise surface smoothness or lead to warping.
Innovation Solution
A transparent heat-resistant laminated film with a thickness of 3 μm or more intermingled layer between layers containing different amounts of lubricant, where one layer has a polyimide composition and a higher inorganic filler content than the other, and an adhesive is not used, allowing for improved handling and reduced warping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a lubricant such as silica particles is added to improve slipperiness, then handling properties are improved, but surface smoothness is impaired
Solution Approach 1:
The film is divided into two distinct layers: a first layer containing lubricant particles for slipperiness and a second layer without lubricant for surface smoothness. This segmentation allows each layer to fulfill its specific function independently, resolving the contradiction between handling properties and surface quality.
Solution Approach 2:
Different regions of the film (front and back surfaces) are given different properties through the two-layer structure. The first layer provides slipperiness where handling is needed, while the second layer maintains smoothness where functional elements are formed, allowing local optimization of properties.
2Ease of operation
If a two-layer laminated film is fabricated with one layer containing lubricant and the other not, then slipperiness is improved, but warping occurs due to differences in physical properties
Solution Approach 1:
The thickness of the intermingled layer is specifically controlled to be 3 μm or more, which changes the structural parameter to compensate for physical property differences between layers. This parameter adjustment reduces warping while maintaining the slipperiness benefits of the lubricant-containing layer.
Solution Approach 2:
An intermingled layer is introduced as an intermediary between the first layer (with lubricant) and the second layer (without lubricant). This intermediate structure acts as a buffer that reduces the impact of physical property differences, thereby suppressing warping while allowing both layers to maintain their functional properties.
3Adaptability or versatility
If polymer films are used as flexible substrates to decrease weight and improve flexibility, then adaptability is improved, but heat resistance is reduced
Solution Approach 1:
The invention uses a composite laminated film structure combining polymer materials with specific layer compositions. The first layer contains inorganic filler particles (silica, alumina, or titania) dispersed in the polymer matrix, creating a composite structure that enhances heat resistance while maintaining the flexibility and light weight advantages of polymer films.
Data Source
AI summary
Provided is a transparent heat-resistant laminated film that has a sufficiently smooth surface to be used as a substrate in a flexible device, and that has excellent handling properties and suppressed warping. A transparent heat-resistant laminated film characterized by having an (a) layer, a (b) layer, and a blending layer located at the interface between the (a) layer and the (b) layer, the thickness of the blending layer being 3 μm or greater.(a) layer: A layer that contains a polyimide composition.(b) layer: A layer that contains a polyimide composition and that has a higher inorganic filler content than the (a) layer.